Janrain has signed up NPR, HSN, and Universal Music Group sites, which includes more than 100 music artist and industry sites like ladygaga.com, justinbiebermusic.com, imaginedragonsmusic.com, eminem.com, and interscope.com. Gigya landed American Idol and Food Network UK.

When users log into one of the company's product sites with their Google+ credentials, they can bypass registration forms and avoid having to create a new username or password.

Google+ Sign-In is largely targeted at developers, who add the Google+ sign-in option to their app or site. But once that's in place, you'll see the "Sign in with Google" and the G+ logo alongside all those "Sign in with Facebook" or "Sign in with Twitter" buttons across the Web.

Next time you want to scour the American Idol lineup, check out Justin Bieber's latest album, or listen to this week's "Wait Wait Don't Tell Me!" program, just click on the red "Sign in with Google" button.

"Google+ Sign-in is a major innovation in social login," Gigya CEO Patrick Salyer said in a statement.

For Android users who sign in to a website that also has an app, meanwhile, signing in on the desktop will automatically give you the option to install that app. Once you sign in on the PC, a pop-up window will ask you to pick your Android device and request permission to install on your phone. It will then appear on your mobile device with one click, Google said.

Universal Music Group has been using social login for more than four years to help ease the registration process and drive engagement on its sites.

"Consumers place a significant amount of trust in their online identity providers, which is why social login is so popular," Janrain CEO Larry Drebes said in a statement. "We're pleased to see Google trending in a positive direction."

Drebes called the integration of Google+ Sign-In "a significant milestone" in his company's efforts to improve customer engagement and marketing among its customers, including NPR, various music artist and industry sites, and the Home Shopping Network.

"By implementing Google+ Sign-In, Gigya's client-base has a remarkable opportunity to spread its content and applications throughout the Internet, helping users discover awesome new experiences," Seth Sternberg, Google's director of product management, said in a statement.

A number of websites already include the new sign-in option, including Fancy, Flixter, OpenTable, Shazam, and TuneIn.

For more, see PCMag's review of Google+ and the slideshow above. Also, get a closer look at Google+ Sign-In in the company's video below.

Stephanie began as a PCMag reporter in May 2012. She moved to New York City from Frederick, Md., where she worked for four years as a multimedia reporter at the second-largest daily newspaper in Maryland. She interned at Baltimore magazine and graduated from Indiana University of Pennsylvania (in the town of Indiana, in the state of Pennsylvania) with a degree in journalism and mass communications.
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